1. Field of the Invention
The present invention deals with a method for performing word processing and particularly a method for performing justification of text within lines to be printed so as to produce uniform margins.
2. Description of the Prior Art
It is well known in the prior art to provide a word processing program of a word processor with the ability to perform right justification at the time that the text is printed. Right justification is an operation in which the words are positioned on each line to produce a document with a flush right margin in addition to a flush left margin. When right justification is used, it provides an even right margin such that lines of printed text are of equal length and do not end within an unequal number of spaces.
Current word processing programs have several problems with respect to the methods they use to perform justification in text. One problem is that the distribution of space between words so that the words completely fill a line to the right margin can result in the occurrence of rivers within the text. A river consists of the coinciding of gaps between words on consecutive lines of text which appear as a meandering white vertical line on a printed page. Although rivers can occur naturally by having the same length or approximately the same length words occurring in patterns within the text, the occurrence of rivers can be exasperated by the introduction of spaces between words at the beginning or ends of lines caused by the expansion of a line during justification. This expansion can cause these gaps to vertically, or more or less vertically, align.
A second problem that is encountered with current methods for doing text justification in word processing programs is that a separate justification routine may be required for each printer device on which the document is to be printed. For example, in a prior art word processing program capable of handling a line printer and a letter quality printer, three separate justification programs were required. One justification program was required to handle the line printer and a second justfication program was required to handle the letter quality printer operating within a fixed width character mode, and a third justification program was required to handle the letter quality printer operating in a proportional character mode. This problem of requiring multiple justification programs to handle multiple output devices can be compounded by the added complexity of attempting to distribute some of the expansion between words and some of it between characters within words.
Therefore, what is required is an improved justification method which will be independent of the output device on which the document is to be printed and which will minimize the occurrence of rivers within justified text.